Blown Head Gasket Symptoms

blown head gasket symptomsI usually get my oil changed at Jiffy Lube because they are convenient and I can’t crawl under my car and change my oil like I used to.

I got it changed there a few months ago and shortly thereafter my car started to overheat and the heater stopped working. If I revved the engine really high it would cool off and if I was idling the engine would get really hot but the heater still blew cold air (this was in February in Utah.

I decided to check my coolant thinking that maybe I needed to get it changed out. When I opened my coolant reservoir it looked like a melted chocolate milkshake… I even stuck my finger in to see what the consistency was… it was thicker than coolant but not by much.

I checked the oil and it was fine on the level and was still that greesy black color. I took my car to my normal mechanic and he said that first thing is that we should do a coolant flush, but that it sounds like my car has a blown head gasket.

I dropped the car off and talked to him the next day and he said that he can’t even get the car to drain, the coolant was too thick. I called the Jiffy Lube and asked the manager there if there was any way it could have been them, he said that the coolant must have gotten bad some other way.

I had the thought that they may have added oil to the coolant instead of the oil reservoir… He ensured me that there was no way they would have done that, but he flushed most of the old coolant out for me and filled it back up with clean, and yes, he did not flush all of the bad coolant, but a great deal… it was chunky.

What this video IF YOU DO suspect a head gasket leak, this talks about my favorite sealer additive.

He also topped off my oil that was now really low. My heater started to work again, but the engine still overheated. My shop guy told me that in order to get my gasket replaced I have to pay $900. I haven’t driven my car since and when I started it I could tell there was coolant somewhere in the engine because of the white smoke and the antifreeze smell.

My question comes to these:

1. Why was the antifreeze chunky and the oil didn’t have any issues at all?

2. I know you’re going to suggest a compression test, is there any way to do that without going to a shop… I am really short on cash and can’t even really afford the $65 or so

3. Is there any other way to tell if you have a blown head gasket? How good is the K&W product and is there any chance it will make my engine worse?

4. Lastly, how hard is it to change out a head gasket? I am pretty good with cars, I just hate working on my only vehicle…


Hey there Brooke

So your engine is overheating……all the time, or just at idle speeds? You DO have white smoke coming out of the exhaust pipe??? Does the engine miss-fire and run bad and does the check engine light come on? Are you continually adding coolant to the radiator?? I would expect all these things to be happening if you had a blown head gasket or an internal coolant leak.

Has your mechanic performed a cooling system pressure test to see if there is a leak in the system? If not get another mechanic, that is the first thing you do in a situation like this!!

I am not real sure what the junk is inside your radiator….it could just be rust, which I have seen “chunks” of rust in a cooling system before and the rusty water will look almost orange/chocolate appearance.

If you were in my shop I would FIRST pressure test the cooling system for leaks….this should also tell you if you have a leak internally to the engine like a blown head gasket. A compression test will tell you if the engine is worn out or there is an internal mechanical problem….which I don’t think you have.

If the pressure test shows that there IS an internal coolant leak then yes, by all means try the K&W Block Seal Additive I talk about on my site….I assume you read my article on how to use it (not like the directions on the can tell you how to use it in the video above)

If your mechanic even suspects there is an internal coolant leak…I would use the K&W additive anyway….it wont hurt anything if you don’t have a leak.

I have a STRONG feeling you will need to replace your radiator though BEFORE you try the block additive. If you have chunks of stuff in your radiator you most definitely have some restriction in your radiator and “flushing” will NOT remove the junk at the bottom of the radiator that is restricting your coolant flow to the engine.

You can get a fairly cheap after market radiator for this vehicle and install it yourself then do the block sealer trick.

The heater core is basically a small radiator inside the dashboard, so I would suspect your heater core is restricted with what ever this chunky stuff is hampering your heater operation. You might be able to remove both heater hoses under the hood and flush out your heater core with a water hose to remove any loose debris that is lodged in there.

Also you need to replace the thermostat….anytime you replace the radiator or do anything to the cooling system.

Keep me posted will ya?

Please share this with your friends,
Austin Davis

Posted in: Head Gaskets

117 Comments on "Blown Head Gasket Symptoms"

Trackback | Comments RSS Feed

  1. Single Woman says:

    1995 4 runner had a improper engine rebuild. Was told the head gasket was put in backwards or inside out. Thermostat was spurting. Old mechanic took it out as a temp fix as we lived on the coast. Marriage broke up, he passed so no asking him about the car anymore. Moved to desert radiator replaced. Overheating worse than ever. Have had two different roommates who are trying to have me get rid of car and jobs require “reliable insured transportation” Heater has been bypassed and landlord and his mechanic won’t help me any further. Says the head gasket is blown and not worth fixing for a 20 plus yr old vehicle too many other “costly serious issues” Landlord is evicting me if I don’t have employment in two days trying to railroad me to a sweatshop call center for $50 a week car pool. Would only leave enough money to pay rent. No food, phone or savings. So it’s not an option. My church is referring me to a shelter in a rough part of town that requires you give up luxuries to grow. I should have said I smoked ciggies and partied so those could be my sacrifices. I’m good with living below my means if I have a budget to work with and don’t have family to turn to. None of these options seem good but they say the 6.0 aluminium 3 ltr engine is gone and “people like me” can’t maintain a car and need to get a bus pass. I know my situation is tough but people who can and do help others do not extend that courtesy to me. I just keep encountering people who are making failure my only option and going to live in a crime ridden part of town is only going to get me mugged or worse.

    • Austin Davis says:

      Wow, I don’t know what to say to all that, I will pray for you and wish you the best, I would recommend you try the sealer as I mentioned in the video and see what happens, not much to lose I guess at this point.

  2. Jesse says:

    I have a 93 jeep grand cherokee 5.2 . I was at a mud rub went in a hole water splashed up in the intake and killed my jeep water wasn’t over the intake or motor. Got it out took the air cleaner out and it started after a few times of trying it did over heat once due to radiator being full of mud. Now it runs fine till it’s getstill to normal temp then the idle drops and has extremely low oil preasusre and smokes if I thouch the gas it goes back up and runs smooth but still white smokes idk what it could be . Please help

    • Austin Davis says:

      Hmm, I think I would run a compression test on all cylinders first to rule out any internal engine damage. A cooling system pressure test would be helpful as well to see if you damaged the head gasket.

  3. Austin Davis says:

    Hard to say for sure, but I would first rule out an external oil leak. Once engine is properly full of oil, does it still smoke? If so, then get a cooling system pressure test to determine if the head gasket has failed…if so, try the sealer I mentioned to repair it.

  4. Austin Davis says:

    I would figure out where the oil went, external leak or did the engine consume it internally due to excessive internal wear. If engine ran out of oil…it might be seized up, thus the clicking noise…unable to spin the engine over due to internal damage. If that did happen, you might be able to pull out the spark plugs, add 2 cap fulls of Marvel Mystery Oil inside the cylinder, let sit up for 30 minutes and then try to spin the engine over with the key.

  5. Austin Davis says:

    You need to find the oil leak/loss issue first. I would assume the engine is running so hot internally without lubrication that it is trying to seize up.

  6. Kathy Ramos says:

    2005 Saturn Ion v-6 So i put oil in it and 30 mins later it started throwing alot of white smoke that smells burnt but my car has not over heated theres no oil in the cool-ant and no milky stuff on oil cap the oil looks normal, please help me what do you think this could be?

    • Austin Davis says:

      I would get a cooling system pressure test to rule out an internal coolant leak, like a head gasket. BLUE smoke is usually from burning engine oil. If it is blue, and oil is getting inside the cylinders….not much you can really do about it beside tear the engine down and rebuild it. using thicker weight engine oil, like Castrol 20w-50 and a can of Engine Restore Oil Additive can help reduce the oil consumption, but not repair it.

      Headgasket leak can be repaired with the additive I talked about on this post.

      • Terry says:

        I drive a 2000 dodge neon. I was headed to work this morning when all of a sudden the car died. I opened the hood and the radiator was spewing coolant and making a boiling sound. My oil pressure light came on. Also the engine will not start again. Suggestions or ideas?

        • Austin Davis says:

          When it cooled down did it restart? If not, you might have overheated to the point that the head gasket has failed and is allowing coolant into the cylinders. Try the sealer I mentioned if that is the case.

  7. Chris says:

    Hi Austin I recently had my timing belt, water pump (the pump was bad originally), and the distributor cap replaced on my 1995 civic. After I picked up my car from my mechanic and driving home the car began to shake violently and jerk forward slightly when I came to a full stop. When I accelerate I feel a major hesitation for the car to accelerate and at one point white smoke came from my tailpipe. I pulled over and all of my coolant was missing but there was no external leak and my coolant reservoir was boiling over with all the coolant gone. My temp gauge did not increase and when I filled the car up again and finished driving home I checked and all of my coolant was gone again having the same characteristics as when I first pulled over. I will replace the radiator cap because the one i had before was fairly worn hoping that may help. The engine also misfired and now it will not crank over.What could this issue be??

    • Austin Davis says:

      Sorry for my delay, trying to keep up with email questions. I would highly suspect they installed the timing belt incorrectly and the repair needs to be redone. They have the engine “out of time”, due to the timing belt installed wrong… is also possible to install the distributor incorrectly, and causing the same “out of time” issues as the belt. either way, sounds like you are going back to the mechanic for warranty.

  8. cameo says:

    I have a 2001 Chevy cavalier. I’m noticing a smell coming from the tail pipe. I just did the water pump no to long ago, replace the seal on my manifold and flushed the coolant system. Then I started getting a burning plastic/rubber smell and the tail pipe smell. Now, every now and then my car hiccups when I start it.i bought new thermostat and sensor for coolant system and can figure out what is causing the issue with tail pipe. I know I need a new flex pipe on exhaust. what should I look for and where should I look?

    • Austin Davis says:

      Sorry for my delay, had a family emergency that took me away for a while. I would get a cooling system pressure test FIRST to see if you have an internal coolant leak…..I dont think you do from what you shared with me. Could be something stuck on the exhaust system that is burning a plastic bag, or from oil leaking on the engine??? Check the tune up material as well, spark plugs, spark plug WIRES etc. for the hiccup.

  9. netta says:

    Hello my car was over heating so i took it to a shop the guy said it was my thermosat gasket i got it replaced and car smoking a little under the hood which the mechanic said its just anti freeze that has to burn off could this be true?

    • Austin Davis says:

      Yes it could be, smoke under the hood could be just some left over coolant that was spilled on the engine, or there is still a coolant leak that needs to be repaired.

  10. Robert sisson says:

    I’ve got oil leak above the water pump and where head meets block my coolant level is good got some deposits of water on top of head bolts when I took the valve cover is it my head gasket and can I fix it without taking head off

    • Austin Davis says:

      I would try the K&W Block Sealer additive and see what happens. It won’t hurt anything, use as per my instructions though…better results than on the can.

  11. Robert M. says:

    i have a similiar issue my 89 camry was overheating on idle but cooling down when fans kicked in or when driven. brand new radiator installed and all fluids were ok but i did a test run and drove it about 1 mile out and the car smoked under the hood and the car died, all the electrical is still up and the starter clicks but no turn over. no leaks found. if i dont find a reason to fix it ima just junk it. its not worth fixing a head gasket.

    • Austin Davis says:

      I would do a compression test on all cylinders to see if there is excess internal wear. Smoke under hood…sounds like there is a coolant or oil leak getting on the hot engine, so a pressure test of the cooling system is called for as well due to overheating complaint.

  12. amber says:

    Hi Austin i was on my way home from work last night and my car started to smoke really bad. It literally looked like it was on fire. Now i just replace the radiator about 3 weeks ago, a new one. The thermostat was reading hot. I was wondering what your opinion was please. I just put an engine in it about 2 years ago also.

    • Austin Davis says:

      Was the smoke under the hood? If so, could be from a coolant leak (white smoke), spraying on the hot engine and you need to check coolant level, if low get a cooling system pressure test to find the leak. Could also be from an oil leak, getting on the hot engine. Check all under hood fluids, and locate the leak.

      If smoke from the tailpipe, WHITE smoke – check the coolant level in radiator, get pressure test, could be an internal head gasket leak
      Blue smoke – due to burning engine oil, something is wrong internally in the engine and oil is leaking inside the cylinder on the spark plugs
      Black smoke – engine is burning too much fuel, “running rich” and a sensor or fuel injector could be bad dumping too much fuel inside the cylinder.

      • amber says:

        There was a hole about an inch long in a hose that went to the heating system and it was leaking antifreeze. Thank u for the advise i really appreciate it.

  13. Jenny hill says:

    Hi, was wondering whether I could get you opinion , I have a ford ranger xlt 55 plate, I started having issues with the truck over heating, temp gauge kept going up to high then back to under half way when going up hill, so we had the thermostat replaced and the issue still happened and it was loosing a lot of water and coolant, we then had the radiator replaced, and we are still loosing water and coolant, for example filled the radiator and coolant bottle on Wednesday, now Friday and coolant bottle empty and radiator took over a 1 litre of water. No long journeys 4-5 miles max.
    There has been times where white smoke comes out the exhaust but it’s not all the time. Some people have said a cracked block, do these sealants work if so for how long?

    • Austin Davis says:

      I would get the cooling system pressure test done FIRST, then if you still suspect an internal leak (not an external leak like a water pump or heater hose etc) then try the sealer per my instructions and see what happens. The sealer will not hurt anything, so would be worth a try if you have ruled out an external leak.

  14. christy says:

    I have an 02 Nissan Altima and every time you let the car set and idle the heat goes cool in it I could rev the engine up and the heat gets hot again I have had the water pump and thermostats changed in it and it still didn’t help what would be making my car do this

    • Austin Davis says:

      Probably low on coolant due to a leak, or there is air trapped inside the cooling system that needs to be bled out. Also check to make sure the electric cooling fan at the radiator is coming on when the engine heats up.

  15. elliott says:

    Mr. Davis,
    I have 2006 mb ml500 at 120000 miles on it. The battery I replaced 3mo ago drained out somehow. When I started my car after recharging the battery, “CHECK ENGINE” light came on. The light went off after I turned on and off the car a few times but white smoke came out from both exhaust pipes. Little chilly and wet weather here in Seattle but more white smoke came out when I gave more gas. I did not smell anything from white smoke. Trouble with a Bad heAd gasket? I let the engine run 20-30 minutes and I drove a few miles but did not feel anything different than before but white smoke.

    • Austin Davis says:

      Sorry for my delay, I have been on vacation. Are you still having trouble? Small amounts of condensation smoke from the tailpipe on cold days is pretty common. Check the coolant level inside the radiator if low, get a cooling system pressure test to help locate a leak you might have. Probably not a headgasket issue…from what you have shared with me.

  16. Chris billard says:

    I have water flowing for my exhaust, a lot if white smoke. Oil is milky and is misfiring. Going through a lot of coolant and no heat. Are they signs of a blown head gasket.? 2005 Buick rendezvous with a 3400 Sfi. Not sure.

    • Austin Davis says:

      Sorry for my delay, Im on vacation. Yes, does sound like an internal coolant leak from what you have said. Get the pressure test to verify, then try the sealer as per my instructions.

  17. jose says:

    when I was driving my car it to started shaking like it was going to turn off when I got to a stop sign so I stepped on the gas and got to a second stop sign and it turned off. the steering wheel got stiff. I turned it back on and drove it to my house it was less than a mile away. then I checked the oil and for some reason there was no oil at all. I put in 3 liters of oil and the car stopped smoking but now that I put it on reverse or drive the car starts to shake like it’s going to turn off and head lights and interior lights flutter like they’re going to turn off. my car has never overheated what could be wrong with it?

    • Austin Davis says:

      Sorry for my delay, I’m on vacation. Not sure what is happening here, sounds like a definite oil leak somewhere though, and I would not drive this vehicle until you have it looked at. The headlights fluttering, can usually be a sign of an alternator problem. Sorry I cant help more, need more information from you. I would advise going to the dealer for a diagnosis, and we can go from there.

  18. Lynn says:

    I have a 2004 Chevy Blazer 4×4 122,000 miles and recently have been losing oil. I am not burning oil that I can tell nor do I have oil leaking on my garage floor. During the earlier part of the year I had leaking oil lines which were replaced. Then I had it in the car dealer back in August because it was smoking, not overheating and there weren’t any warning lights. I was low on oil and some was added to make sure it was ok to drive to go get looked at. While on the way to the dealer it caught fire. The Dealer said oil got on the manifold but how did it get there? Oil was not spilled while being added. They checked and found no signs of leaks either. So since August I have lost 1 1/2 quarts of oil. I have only put probably around 1900 miles on the truck since the August issue. I have no oil in my antifreeze so I don’t think I have a head gasket issue. So how am I losing oil?

    • Austin Davis says:

      Humm, sounds weird alright. Either there is an external oil leak and you are just not seeing it, or you are burning (consuming oil internally to the engine) and its just a small enough leak that the engine is burning it off efficiently so there is no real tailpipe smoke that is visible and not enough oil getting on the spark plugs to cause an engine missfire or a check engine light to come on.

      The fire does not make much sense to me either, that had to be a lot of oil, or FUEL on the manifold to ignite. I have seen tons of vehicles with lots of engine oil dripping on the manifold and it just burns off, never ignites. I am wondering if you had/have a raw fuel leak or a transmission or power steering fluid leak..which is more flammable than thick engine oil. I think I would proceed this way if you were in my shop.

      1. Make sure engine is totally clean and dry, then drive vehicle a few 100’s miles and recheck for external leaks. Also make sure the rear main seal where the transmission and engine meet is dry

      If no leaks

      2. I would do a cylinder compression test to see if there is excess compression loss inside the engine, which will consume oil

      3. I would then inspect the spark plugs for evidence of an internal leak oil leak, will make the plug black and greasy on the electrode end

      4. I would check the PCV system, replace the valve and make sure there is proper vacuum, this is how the engine breathes. Also check the air filter to see if it is oily feeling, which happens when there is too much internal engine pressure.

      5. If all those check out ok, I would remove the cylinder heads from the engine and do a valve job, which is basically rebuilding the top half of the engine. Cost, about $1,500 – $1,800

      Oil is cheap, so if its burning it, I would start using Castrol 20w-50 weight and a can of Engine Restore additive on each oil change to thicken the oil and reduce the consumption and save some money for a newer vehicle.

      • Lynn says:

        Hi Austin,
        So here is the newest adventure with the 2004 blazer. I had to take it back to the Chevy Dealer yesterday here were my issues…
        1. My headlights and dashboard lights were flickering and wanting to die out when parked or idling. The voltage Gauge was bouncing around like crazy. Of course my first thought was the Alternator but it tested fine. (I was told it was idling low and had a lot of carbon built up which was causing that issue. So they cleaned everything.)
        2. Also in the morning I noticed what looked like watery oil on the garage floor so I wanted to see where it is coming from. They said I have a small leak coming from the timing belt cover but due to the age of the vehicle it’s not worth fixing for the cost of the repair. Just keep an eye on the oil level and fill in between oil changes if needed.

        But they did see I have a lower intake manifold leak. I need my truck for now so I did get it fixed today but when I got home I read up on what it was and how they fixed it. I saw there was evidence of coolant in the engine but they cleaned it. I never had any signs of the leak as in overheating, losing coolant that I could see, or not having heat…..

        I did have the white smoke from under the hood and the fire back in August. Could this have been the cause of the smoke and fire?

        Also do I need to have concerns that there could be damage to the head gasket or engine that they did not see due to me not knowing how long I had this leak? So far everything is running great and not hearing any noises or having lag but I only drove it 2 miles home. I will hopefully be able to get rid of it next year but in the meantime I need it to get to work and my son to school on a daily basis. I don’t need to get stranded in the cold.

        • Austin Davis says:

          Well, white smoke UNDER the hood would be from a coolant leak dripping on the hot engine, which is due to an external coolant leak not an internal head gasket leak. The lower intake leak, might be the culprit of that smoke/leak. The K&W Block Sealer will not help with the intake leak, but a can of Barr’s Radiator Stop leak additive MIGHT help repair or slow down that intake leak.

          I don’t think there is any internal head gasket damage from what you have shared, just make sure the engine does not overheat, so keep the radiator full of coolant.

  19. Becky Bender says:

    I have a 2003 chevy impala i started it this morning and it was shaky with a rough idle and flashing check engine light. White sulfur smelling exhaust. I rode about one mile to get a code from auto zone they said multiple misfires and vacuum leak was the code. When i drive it loses power and stutters when i try to accelerate. Also when i checked under the hood my coolant reservoir was empty

    • Austin Davis says:

      This could be an ignition coil, spark plug or spark plug wire type of problem and the engine is “missing”. To rule out a head gasket issues, top off with water and get a cooling system pressure test to determine if you do have an internal or external coolant leak. A blown head gasket can cause the issues you are having, but so can the other items I mentioned. Please see a qualified mechanic to check into this further, feel free to contact me again once you have more information. Fingers crossed its something easy and cheap 🙂

  20. Dominique Bredy says:

    I have a 1994 Mercedes c220 with 164k. The problem that I have is oil in my antifreeze. The mechanic said the radiator was rusted and was leaking. So radiator was replaced and flushed by a Mercedes dealership. I requested that Mercedes antifreeze be used and they did. After receiving the car and driving it for a week The same issue returned. The mechanic said he doesn’t think its a blown head gasket. There is no antifreeze in the oil dipstick and the trans fluid is normal. There is no white smoke coming out of the tail pipe. I have been told its cool be the oil cooler. I am not sure which direction to go or what to do. I am hoping its not a gasket. The car is not overheating either. I do have some codes though; p0441-p0411-p1700. Please help me save my baby Benz.

    • Austin Davis says:

      This is going to take a little more investigation by your mechanic. It could be an oil cooler issue, which would be a fairly cheap GUESS…but, I don’t think this vehicle has an external engine oil cooler that you can change. You might be seeing transmission fluid (not engine oil) because the transmission fluid cooler is shared by the radiator, but since radiator is new…probably can rule that out too.

      A head gasket issue might be all that is left, and using the sealer I talked about on this page would be worth a try. You can have a head gasket problem and not have the more common symptoms as I describe on this page, its rare but it can happen. Milkshake looking engine oil is a sign coolant is leaking internally to the engine, but it can also leak backwards…oil into coolant.

      Those codes you are getting, mostly are emission system related and should not have a bearing on your current issue. Here is more info on them and the p1700 is transmission related, nice video explanation

  21. Cranesha taylor says:

    I recently noticed my antifreeze getting low in my car and my garage having spots where my car has been parked. Took my car to get a quick look at he tells me my car has a small leak. But whenever I turn my car on and put the heat on it blows out cool until I drive my car. Which then it works like normal gets extremely hot and everything. Sometimes though I I have my heat on too long my car gets a little foggy and I would have too turn on the defrost and within 20 seconds it’s clear again. .but if I park or even stop at a stop light it gets cool again. I need an oil change I’m definitely over my mileage and have a leak do u think I could possibly need a new water pump, head gasket or just need to fix the leak? I would like to know some type of idea before I pay tons of money on something that doesn’t really need to be fixed.

  22. Marsanne says:

    Hi. I have a 2005 Buick Lacrosse CXL. It kept running hot, so we changed the thermostat, then found a small 90* hose that was cracked and leaking. We changed it too. Then the floorboard ended up full of water, so we changed the heater core. There is still a leak, because when I sit with the car idling, there is water on the ground under the passenger side of the car. Plus, just since the heater core was changed, there appears to be a wet spot where the exhaust comes out of the car. Any ideas? Thanks.

    • Austin Davis says:

      Get a cooling system pressure test to help you locate the leak. Could the water under the passenger side be from the A/C drain….cold clear condensation water…not coolant? There is usually small amounts of moisture coming out the exhaust system, if you look under the car at the bottom of the muffler you will see a drain hole for moisture and sometimes that can get clogged up with rust and carbon. As long as water is not spitting out the exhaust with clouds of white smoke, I would not worry too much about it…probably normal exhaust.

  23. Colby says:

    I have been driving a 1998 Buick for the last 4 months. When I bought the car, there was concern about a blown head gasket due to the hoses being soft and greasy. However, since I only need the car for a year, drive short mileage at low speeds, and the price was right, I bought it for cheap. It had been treated with a block sealant. A week after I bought the car I had the engine flushed and the oil changed. Immediately on the way home from the shop it started to overheat. I brought it back into the shop and they said there was nothing they could do short of replacing the gasket. They also said that the sealant had made the coolant super thick and sludgy. The car wasn’t worth this procedure, so I began to drive it home, and on the drive home thee was a sort of belch and the car almost immediately returned to the right temperature. Haven’t had a problem with it in months– although occasionally the thermostat will creep up until it belches and returns to normal. Then this morning it starts overheating again. Only overheats in idle or low speeds. The heater blows cool air during this time. When I can get it up to speed, it does a sort of half belch and the temperature normalizes and the heater puts off the hottest heat you’ve ever felt. No smoke from exhaust. When you pop the hood you can hear the coolant bubbling and boiling. The hose from the coolant container is cold and appears limp. I’m hoping a coolant/heater block flush can hold me over for a few months. Is this advisable? Like I said, I need the car to last for 8 more months and then the wheels can fall off of it. Thanks!

    • Austin Davis says:

      My gut is telling me this is either a restriction in the radiator and needs to be replaced, or there is a problem with the thermostat and it needs to be replaced. Get a cooling system pressure test first to rule out an external leak. Although, you said it overheats at idle and low speeds, and the heater is not hot. Either the radiator cooling fan is not working, or the system is low on coolant. If no leaks, radiator fans working…you might just have an air pocket in the system which needs to be bled out. I dont think this is a head gasket issue from what you have shared with me.

  24. Aj says:

    Hi, Thanx a ton. Your words have given me a direction!

  25. Aj says:

    Hi, I drive a 2005 Force Van (It has Merc-Benz OEM engine). When I run the AC on idle, everything remains OK but when I start driving, sloely, the tempertaure rises and I smell burning (smell of burning oil or something like that) and at times see fumes from underneath the body (middle). The moment AC is switched off, temperature turns normal and vehicle runs smoothly. I face a similar situation (Without AC on) in hills/mountains where vehicel temperature starts to rise and smell comes out.
    I feel rightwards drag on braking (always) but the cooling system is working normally (recently flushed).
    Please help

    • Austin Davis says:

      Well the first thing that comes to my mind is a possible radiator restriction causing an overheating condition. Running the A/C just adds an extra heat load to the engine/radiator so does driving up hills etc. The smell could be just the engine getting hotter than normal and burning off some oil/grease residue or the exhaust system could be getting hotter than normal causing the smell.

      I would first get a cooling system pressure test to make sure there are no coolant leaks, then check the radiator for a restriction. “Flushing” really does nothing except remove some very light surface junk, but does nothing for removing the rust and mineral buildup at the bottom of the radiator.

      Just to rule out a sticking brake caliper, I would jack up the vehicle and spin each wheel by hand, then start the engine and apply the brakes a few times and re-spin each wheel again looking for anything abnormal.

  26. jennifer says:

    I have a 2005 kia optima…. we had a milky substance in the overflow tank so we replaced radiator hoses and radiator, flushed out overflow tank and it was all good till about a week ago. I went to tilden and got ky oil changed. 2 days later car overheats and oil flashes. We put 2 quarts oil in the car and still overheated. What could be the problem?

    • Austin Davis says:

      Well I would first start off with a cooling system pressure test to help you determine if you have an internal or external coolant leak. Then I would check the engine for an external oil leak, like from the valve cover gaskets or oil pan drain plug…two common leak areas.

      You could have a head gasket leak, but rule out an external leaks first. If the engine gets low on oil, it will cause it to run well as do internal engine damage.

  27. Jessica hadder says:

    I had a pressure test done and there is a leak on the side of the engine with hoses attached to it. After I had the test my engine started jumping right after I took off, is that normal after that test? It was fine before and now my check engine light is on and the leak is bigger.

    • Austin Davis says:

      So the leak is EXTERNAL not internal like a head gasket right? The test should not have done anything to turn the light on unless they unplugged something or knocked something loose.

  28. Alicia says:

    I just recently went to the auction on Saturday and purchased a 2003 Cadillac Seville SLS with 99,668 miles. It was inspected and passed on Monday. Monday night it over heated and told me to change engine oil and check coolant level. So on tuesday I went to Jiffy Lube and got my radiator flush, oil change and topoff all fluid levels. Temperature ed gauge still was moving not in the RED area. Suggested a new thermostat so got one and the still goes passed halfway mark. The gauge moves back and fourth while im driving. Dont know who is telling me the truth. I went to Aamco and the said I need to replace my hose they are lean bank 1 and 2. Someone told me to get rid of car. Please help this is my first car… What could be wrong?

  29. melinda says:

    Over the past winter I had no heat. Just recently I had someone put a thermostat in my 2002 Nissan altima because I was leaking coolant bad and after thermostat it hasn’t leaked but I smell burnt coolant and my car makes a rattle sound when I’m stopped and it just recently did that and also when I’m stopped and it rattles it acts like it will die. In the mornings when I start it and it shakes and goes away. No heat still and no white smoke and oil looks ok. Its acting like it wont start now. What is this??

    • Austin Davis says:

      Humm, I don’t really know either from what you have shared with me. I would get a cooling system pressure test FIRST, before you do anything else with the cooling system, or overheating issue. The noise, have you checked the engine oil level? I would check all underhood fluids first. An engine low on oil or coolant will produce the symptoms you mentioned, so I would be a little concerned there is a lack of lubrication or cooling issue happening. No heat from the heater, is a tell tale sign there is not enough coolant in the engine to produce the heat, and the pressure test should help you locate any possible coolant leak you are missing.

  30. Nathan says:

    1999 2wd 3.0 Ford Ranger. Replaced heads(with brand new). Followed torque specs/everything to a t. Added water to radiator. Checkes oil, has water in it. Did I put heads on wrong or is something else causing mixture?

    • Austin Davis says:

      Hummm, I would check compression on all cylinders to see if one or more has weaker compression. If so, either the head gasket did not seat properly or maybe the heads were not machined properly or the block is warped which allows a gap in the gasket to block surface. Also….maybe you just spilled coolant in the oil during the install, its very common to have happen.

  31. Anonymous says:

    check transmission oil. may be a leak in radiator between transmission oil cooler and coolant

  32. Scully says:


    I had a mechanic check out my car. His only focus was one of my fans wasn’t working. I do have 2 fans. It appears the fan, on the drivers side of the radiator has 4 arms and doesn’t spin. The 3 armed fan on the passengers side spins all the time. I did change out one of the relays with no difference. What is the electric radiator fan? Is it one or the other fans? And is there a certain temperature the 4 armed fan will come on, so it actually is working, but only at certain temps?

    The belt(s) is in a plastic enclosure beside the motor, but my main concern now is a possible small head gasket compromise. Apparently there is a “combustion” tester I was told to use to check for the head gasket leak. Would the stop leak stuff work on this if that is the case?

    A week ago, I removed the old thermostat and replaced it with a new one. Still having the same overheating problems and no hot air coming from the heater. I did have a neighbor who came to help at the last second and popped the thermostat out without taking note or where the button/divot thingy was positioned. I’m wondering if I flip it around, would that help? Or do I need to get a Toyota original part?

    As for the fan, could it be the motor? The sensors? The fan itself? And how long do I run the car trying to get an airlock out of the system?

    Thank you,

    • Austin Davis says:

      Hi, sorry for my delay have been out of town and just plain swamped with questions lately.

      You usually have 2 electric cooling fans, one for the radiator and 1 for the A/C condenser.

      So turn on your A/C compressor and see if one of those fans comes on. Then the other one will be for the radiator.

      As far as no heater/hot air. I am assuming that is because there is no hot coolant circulating in the engine. When the engine is warm, feel both upper and lower radiator hoses and the two heater hoses going to the passenger side under the hood. They should all be hot, use a rag to not burn yourself.

      If there is a huge difference in temp on those hoses there is a restriction somewhere. The radiator fan needs to cycle on and off as the engine heats up. Usually, the fan motor itself is the problem.

      It still sounds like you need to find a better mechanic, and I would spend the $100 to get a professional diagnosis before you do anything else.

  33. Brittney says:

    Hello Austin

    I got my housing gasket changed/replaced on my 2006 BMW 325i and I would say 2 weeks later my Air/Heat stop working completely. Never had a issue with my AC/Heat until after this was done on my car. I took my car back to have guy double check and the coolant was fine and the fan is still working. Car is NOT over heating either. So i am trying to figure out what happend and what i can do to fix. Also, before I gottent he housing gasket fixed, I had my spark plugs replaced and my value cover replace as well. Thanks

    • Austin Davis says:

      Do you know more about this “housing” gasket? I am not sure I understand what it is you are referring to. There is a thermostat housing gasket that will leak coolant, was that it?

      Now you said you do not have AIR/HEAT, so you DO have cold air conditioner air? Or you have no air coming from the vents at all?

      Can you feel air coming from the defroster vents or the floor heater vents, and can you still hear the blower motor making noise in the dash…or is it quiet?

  34. Bea says:

    Austin, I am desperate for help with my Honda Civic (2002). It started overheating a year ago, so we got a new radiator. Then last week, the car overheated again and I had to fill the radiator with water three times in a 30 minute trip home, because it was steaming out. The mechanic took a look at it immediately and was surprised that the lid on the radiator was so hot that the rubber under the lid was melted. He ordered a new lid that doesn’t fit or seal well and had us pick up the car thinking it was ok. He did the pressure test on the radiator for a leak, but there was no leak. Then, when I took it for a 20 minute drive, it overheated again and I had to fill the car up with water three times (this time much sooner between fillings than the previous three fillups). He is now saying that it may be the head gasket blown and is having a Honda specialist look at it and says that it will cost a lot to repair most likely if it’s a head gasket blown. What do you think????

    • Austin Davis says:

      Bea, I think you need a new mechanic!

      If he replaced the radiator cap (assuming that is what you mean) but it does not seal correctly…then there is a leak and it can not pass a cooling system pressure test. If the system can not hold pressure then the coolant will just leak out.

      I would start from scratch with a new mechanic.

      1. Pressure test cooling system for leaks
      2. Check radiator electric cooling fan operation
      3. Check radiator for a restriction
      4. If they still suspect a headgasket leak, I would do a compression test on all cylinders to make sure the engine is not showing signs of excessive wear or damaged caused by overheating. You can then try the K&W Engine Block Sealer additive I mention on this page, but use per my instructions.

  35. Scully says:

    Over the last week, my engine was making a high squeal. I thought perhaps it was low on oil (since I’m overdue for a change, but no money), so I added a quart of oil. Seemed to help. The squeal only happening a few times, but significantly improved. Then yesterday, I’m driving and there was an explosion under my hood. Water everywhere, on the ground etc, white billowing smoke and the hood even rose up a couple inches. Come to find out, after letting it sit approx 20 mins, the upper radiator hose had blown completely off and sat 4-6″ from it’s origin.

    Got a new hose, added some water, and a complete bottle of coolant/antifreeze to my 97 Toyota Camry V6. Now for the question(s):

    On short trips around town, less than 10 miles, my temp gauge rises to the highest point. I understand the white smoke that accompanies it is mostly or partly the antifreeze burning off the engine. When I set my hand on the hood, it is cool to the touch. However, why am I over heating? And now, as I brake, I can’t say for sure but to me it sounds like the fan may be off kilter and nicking something. Do I need to replace the thermostat? And readjust the fan? Or is this more complicated/serious?

    Thank you in advance for your help.

    • Austin Davis says:

      This could be something serious, and I would advise you to have a local mechanic check this out before we do more damage driving it. The squeel you heard was most likely a fan belt that was slipping, could be due to coolant (which is slightly oily) being sprayed onto the engine and the belt, or there could be a problem with the belt/pulley alignment.

      If the engine runs hot at low speeds or at stops I would be suspect of a faulty radiator cooling fan motor which is not coming on. OR, there is an air bubble in the cooling system that needs to be bled out.

      If you did not have this overheating issue before the radiator hose replacement you could have some air in the system that needs to come out. When the engine is hot you should have a hard time squeezing the upper radiator hose together with your hand…use a rag it will be hot. If you can squeeze it together, I would suspect either a coolant leak somewhere or air in the system and the system is not pressurized properly.

      And, on the noise you are hearing when you brake…check the electric radiator fan and see if it is loose or wobbly. The fan should come on and off as the car sits at idle for awhile and the temperature heats up.

      Check those items and get back to me if you still have trouble.

  36. Bobby says:

    My 1986 buick regal needed water so I filled it up. On my way home It started smoking. Now, it was night time, so it wasn’t very easy to see, but I COULD see smoke coming out of the hood. Not the muffler but the hood itself. It looked white but it wasn’t very thick. Is this always a blown head gasket? I had a guy who knows a lot about cars check it out and he said all I needed was a new thermostat. But now I have people telling me that it sounds like I need a new head gasket..(they didn’t look, just said from what it sounds like). So what does this sound lie it could be? Thanks..

    • Austin Davis says:

      If the smoke came from under the hood I would suspect a coolant leak somewhere under the hood and not a blown headgasket. I would get a cooling system pressure test FIRST if you can not find the leak with your naked eye. The smoke is from coolant getting on the hot engine parts.

      Hopefully just a bad radiator or heater hose, but seriously doubt its a thermostat problem.

  37. Liz says:

    You seem very knowledgable and I am desperate for an honest opinion. This original post caught my eye because the same thing (almost) happened to me right after I had my oil changed at Jiffy Lube in February 2013. I started smelling an antifreeze type smell whenever I turned my heat on. I originally didn’t pay it much mind because i figured they topped off all of my fluids and maybe some spilled and when that particular part got hot I could smell it. I had my antifreeze checked 2 weeks after because I was still intermittenly smelling the antifreeze and i was told there was oil in my antifreeze. I took the car a week later back to Jiffy Lube to try and find out what happened. This is where I am confused: my car runs fine – it is not overheating, I do have heat, I do not have white smoke billowing out of my tailpipe and I am only down 1/2 quart of oil since having the oil changed a little over a month ago. (Ford Windstar – 2002 – 125,000 miles). So Jiffy Lube said it looks like someone put oil in your antifreeze but of course they were not going to admit to it. He flushed out the reservoir and added fresh antifreeze and told me it was safe to drive. This morning (4 days after the fresh antifreeze was added) I did see some white smoke coming out from under the hood – right where my antifreeze resevoir is. i had turned the heat on full blast and was idilng for about 5 minutes. As soon as i turned the heat off and drove off, the white smoke stopped. At the same time I saw the white smoke, I could smell that antifreeze smell coming through the heater vents. I proceeded to my destination – about 30 miles away and did not turn the heat on at all. There was once during that trip where it felt like the car didn’t really want to go but that was shortly after the white smoke siting. What do you think? Blown head gasket?

    • Austin Davis says:

      Hi Liz,

      No, this really doesn’t sound like a head gasket type of issue. I would HIGHLY recommend you go back to Jiffy Lube (or somewhere else if you want) and get them to do a cooling system pressure test.

      This simple, fast and cheap test will let you know if you have a coolant leak, either internal like a headgasket or external like a hose or water pump etc.

      Smoke under the hood would lead me to assume you have an external coolant leak under the hood..white smoke out the exhaust pipe would indicate a headgasket issue.

      Since you also said you smelled coolant inside the car, you might have a leaking heater core. Pull back the carpet on the passenger floor up under the dash area and feel the carpet and the “jute” material under the carpet to see if it is wet..and oily feeling.

      If it is, that is probably due to coolant leaking from the heater core inside the dash down onto your carpet. When you turn on the heater you are blowing air across the heater core and smelling the antifreeze inside the vehicle.

      It can also leak down on the passenger side of the vehicle under the hood..and would cause the smoke if it gets on the hot engine. A leaking heater HOSE on the passenger side under the hood might also be a suspect.

  38. Walker says:

    I like your post, thought I had a blown headgaket but from what you are saying I think I just have a leak or maybe a problem with the radiator. I will look into this further.

  39. Jerry says:

    By far one of the best explanations of this I have been able to find. Gonna try the KW sealer today as well. Fingers crossed for me too please.

  40. Chris says:

    Hi Austin, I have a 1990 Jeep Grand Wagoneer that has recently developed a few symptoms of a leaking head gasket. It may have started when it overheated 3 times on a road trip I took it on with some of my buddies. It has been fine for the past 6 months after I replaced the radiator and I’ve used it for long 2 trips since, but I fear it may have caught up to me. Lately more water than usual has been coming out of the exhaust on cold start ups, and it has been running hotter than usual. The temperature will fluctuate up and down depending on the type of driving I’m doing but it is not getting anywhere close to overheating because the previous owner put in the wrong thermostat so it runs too cool anyways. There is an odd antifreeze leak on top of the engine that appears to be coming from the thermostat housing, but I’ve been checking and adding antifreeze accordingly so I know it isn’t low. There is no milky oil or antifreeze. The one thing that really worries me is that when I decided to look and see if there were bubbles in the radiator when it was running, there were no bubbles that I saw but the coolant level rose and began to pour out. I don’t know if I’m being paranoid but I don’t want to lose my daily driver for a week, or however long it takes my dad and I to tear down the engine.

    • By Austin Davis says:

      From what you told me so far I don’t think you have a headgasket leak, but that external leak at the thermostat housing will definitely cause a problem and needs to be fixed.

      Any leak in the cooling system will not allow the proper pressure to build up in the radiator. So fix that leak.

      The coolant coming out of the radiator when the engine is running is normal thermostat operation, so no worries there.

      Fix the leak and take a test drive, get back to me if you still have problems.

  41. Carly Anne says:

    Wonderful site. A lot of useful information here. Added you to my Facebook wall.

  42. Ginanoelle says:

    My daughter car 2002 GrandAm, overheating. First at 6 miles, then 2-3 trips like this. Changed the serpetine belt, water pump and thermostat. We cant afford this-and it still overheats. The heater blows cool air. Bleed screw done. Now how much to change radiator, is that problem? We dont know what to do now. Talked to 3 mechanices, seems like no one knows the problem.

    • By Austin Davis says:

      If there is no hot air coming out of the heater, then 1 of 3 things is happening or not happening.

      1. Not enough coolant inside the radiator and engine, due to a leak somewhere which you need to have a mechanic perform a cooling system pressure test to find and repair the leak.

      2. There is enough coolant inside the radiator, but that hot coolant is not circulating throughout the engine and heater core for the heater to work properly, and the engine is overheating because of the lack of circulation. Could be a restriction in the radiator that you can not see or “flush” out, or there could be a restriction in a radiator hose that is kinked closed etc. that is restricting flow of coolant.

      3. The thermostat is stuck and not allowing the flow of coolant throughout the system.

      If 3 mechanics have looked at this and are scratching their heads, you really need to find a real mechanic. This should be a pretty easy repair, if they do proper diagnosis and rule out things as they go.

      1. Pressure test the system for leaks (if radiator is low on coolant)
      2. Check for a coolant restriction

      should point you in the right direction.

  43. Ian... says:

    DO NOT USE K&W on a 1994 Camry. I just did this and only managed to clog my heater core completely up and my car will not circulate coolant through the system causing it to over heat. Blew the radiator up from excessive pressure as well. I went from a small amount of coolant in the #3 cylinder to coolant in my oil.

    • By Austin Davis says:

      Totally impossible!

      Let me explain how the product works. There are small flakes of copper inside the can of K&W Block Sealer. Those copper flakes must come in contact with extreme heat and combustion to melt and fill in any hole inside the engine block or in a tear in the head gasket. The coolant itself (inside the radiator, heater core etc.) is NOT hot enough to melt the copper flakes. Those flakes will just remain harmless flakes that will drain out.

      Second, the heater core can NOT cause the engine to over heat. You can totally block off the heater hoses with a pair of pliers and nothing will happen. The coolant going to the heater is coming from a bypass tube off the water pump. There is not as much pressure on heater core, and if you block off just one of the heater hoses the coolant will bypass at the waterpump and circulate through out the rest of the system with no problems. So no excess pressure will happen.

      What probably happened to you, is your radiator WAS restricted at the bottom, and the original cause of your overheating. I have used this product 100’s of times, it works….period. But, it will not cure a restriction in the radiator or anywhere for that matter, only a new radiator will do that. A 1994 Camry with a super thin and easily restricted aluminum and plastic radiator and if its original, I would highly suspect it to be clogged with rust and calcium.

  44. Rob says:

    Thinking of trying the K&W seale, but you suggest –
    Remove ALL coolant (including antifreeze) from the radiator and engine. How do you do this on Fiat Palio 2009 model ?

    • By Austin Davis says:

      Try removing the lower radiator hose and flush out as much of the coolant/antifreeze as you can. Top off with plain tap water and the can of sealer and drive for 500 total miles. you will NOT have FREEZE or boil over protection during this time. So if it is freezing out, make sure to protect the engine and radiator. Put car in garage, and have a drop light under the hood. Remove the rad cap (or reservoir cap) if really freezing cold outside.

  45. Rob says:

    Hi Austin, I already replaced head gasket, thermostat, temp switch, reservoir bottle and cap (Fiat Palio’s dont have a radiator cap), also had engineering works skim cylinder head, plus they tested the valves and confirmed cylinder head is ok.

  46. Rob says:

    When driving the temp gauge is just above 1/4, if idling long in heavy traffic temp gauge is just below 1/2, so car does not have a overheating problem. It seems a little water leaks out water reservoir / water bottle cap when car is stationary.

    Combustion test / block test points to exhaust gas leak. Not sure if its head gasket or intake manifold.
    How do i know wh

    • By Austin Davis says:

      I would replace the reservoir bottle and cap and see what happens. You have not mentioned any of the common head gasket symptoms that would have me concerned. Rule out the easy stuff first.

  47. Rob says:

    Vehicle is a fiat palio active (2009 model).
    I am now driving the car for 12 days after collecting it from garage – As mentioned before, I replaced (head gasket, thermostat, temp switch, water bottle, water bottle pressure cap – Palio’s dont have a radiator cap), also had engineering works skim cylinder head, plus they tested the valves and confirmed cylinder head is ok.

    When starting car in morning (engine cold), the car stuttered in 1st gear on day 3 to day 9, thereafter its gone (no more stuttering when cold). Only issue I still have is that when I fill water bottle from 2cm below min. to max in morning, I need to refill it next morning. Took car to radiator shop, they pressure tested the cooling sytem – no leaks. They then did a combustion test (the liquid turned yellow – meaning that there is gas (CO2) in the cooling system (so head gasket is leaking exhaust gas).

    How can head gasket be blown again ?

    • By Austin Davis says:

      Hi, I am not familiar with this vehicle but the concepts are the same on all vehicles. If you are continually adding coolant to the system, either you have an external leak like a radiator hose or water pump leak or you have an internal leak like from a head gasket or crack in the block etc. or the initial head gasket repair was not done correctly and there is still a leak in the head.

      A cooling system pressure test should show any leak, either internal or external if the test looses pressure. The combustion gas test, they are hard to interpret in my opinion. Yes, they can prove that exhaust gases are present in the coolant but they can also give false positive results as well if not properly administered.

      The stuttering in the morning could be due to coolant leaking down inside the cylinder over night and getting the spark plugs wet, which will cause an engine miss to occur…and the stutter you feel until the coolant burns off.

      Or the stutter you feel could be due to fuel leaking down inside the cylinder saturating the spark plugs and taking a while to burn off.

      There are also sensors that only work on cold starts, and you could have an engine sensor issue.

      I cant remember, did you try using the K&W sealer as per my instructions on this page? I dont think you have anything to loose by trying it at this point.

  48. Rob says:

    When starting car in morning (engine cold), the car stutters in 1st gear (almost as if idling is out) for the first 2 km, thereafter once engine is warm stuttering disappears.
    Water level when getting to work is 1cm below min mark, before returning home I add a glass water, water level at min mark. When arriving home water level is still at min mark. Next morning before going to work water level at 1cm below min mark.

    Is the cause of stuttering when engine is cold due to thermostat stuck open ?
    What could be the cause of 1cm loss of water overnight ?

    • By Austin Davis says:

      This could be lots of things. Worn out spark plugs, weak compression in an older engine, lack of fuel pressure to the engine, too much fuel inside the engine due to a fuel pressure regulator leaking or a fuel injector leaking, even a headgasket leaking cooling inside the cylinders that takes a few minutes for the spark plugs to burn off and smooth out.

      pressure test first, then if things are ok, maybe inspect the throttle body and clean as needed. This tends to gum up over time and a cleaning will help smooth out the idle speed. There are also sensors and relays that only work during a cold start, so reading your onboard computer memory if there is a check engine light that is coming on while you are driving would be the next thing to look at and reading your computer codes with a scanner should be done next.

  49. Rob says:

    Replaced water (reservoir / bottle) cap on day 3, now water has stopped leaking out of water (reservoir / bottle) cap. Water level is now between min and max mark, temp gauge is now closer to the 1/4 than the 1/2 mark when driving or idling in traffic.

  50. Rob says:

    After replacement of (head gasket, thermostat, temp switch and water bottle) the temp gauge is between 1/4 and 1/2 when driving or idling in traffic.
    After driving about 30 km I stopped and checked water reservoir / bottle. Found foam and bubbling in water reservoir / bottle, can see a little water has leaked out water reservoir / bottle cap, you will hear a hissing noise near water reservoir / bottle cap every now and then. Water level in water reservoir / bottle is on (min) mark. On day 2, filled up water from min mark to just below max mark, after driving for about 20 km checked water level, was 2 cm below min mark. No foam, very little bubbling, temp gauge is between 1/4 and 1/2 when driving or idling in traffic.
    Any suggestions as to what the cause could be ?

    • By Austin Davis says:

      Since you are having to add coolant, I would get a cooling system pressure test done first, to see if there is still a leak somewhere. The hissing noise could be due to overheating and the temp gauge on the dash is not telling the truth, or there could be a small coolant leak somewhere on the engine and you are hearing the hissing of that coolant on the hot engine.

      Either way, rule out a leak first, then check for a restriction in the radiator, check electric cooling fan operation etc.

  51. harris says:


  52. Angela says:

    Hello, I recently bought a 1999 Chevy Blazer for my 17 year old son. We only paid $500 for it and the interior/exterior is in really good shape with 120,000 miles on it. It runs good, but the owner told me it had a cracked head gasket as well as the spark plug wires. So….I had this replaced, but it still has an almost overheating problem. The temp gauge goes 3/4 of the way to the red, but doesn’t overheat. There is no white smoke coming from the engine or the exhaust and it runs pretty good for being as old as it is. I took it to a local mechanic today that I think is trustworthy, but his response wasn’t clear to me. He did a pressure test and said that there were not any leaks, but it wasn’t holding pressure and the oil level was increased which leads him to believe that its either the manifold or a cracked head. On a side note, I didn’t tell him the work I previously had done. In order for him to tell me exactly what the problem is he would have to start taking it apart, which I would have to pay a two hours of labor for and then if it was one of the two problems then its going to cost around $400-$900 to fix. Do you think he should have been able to give me a better diagnosis from the pressure test? Any help or suggestions would be greatly appreciated. Thank you.

    • By Austin Davis says:

      I would find another mechanic and start from scratch with your complaint. If you are constantly adding coolant to the radiator then there has to be a leak somewhere and the pressure test is the first thing that should be done.

      I’m away on vacation but you can search my site for “engine over heating” and read more about other causes of running hot and how you can rule things out yourself to help locate the problem. Don’t jump to the “yiu might have a blown head gasket” conclusion to quickly. When you hear that it usually means the mechanic is guessing…and that will cost you lots of money.

      The sealer I talk about on this page really works, if and only if you are certain the headgasket is the culprit.

  53. christina says:

    NEED HELP PLEASE!!!! im having a similar problem but it has been ongoing for about 6 months. i have a 3.5L V6 2009 dodge journey. it has overheated several times and we have done the work in this order to it: changed thermostat, car didnt overheat anymore for about 3 months, overheating started again, there was a hole in the radiator, repaired the radiator by taking it out and welding the hole, no overheating for about 2 months, then overheating started again due to a crack in the radiator reservoir, which was also changed, no overheating for a week, check engine light comes on and reads cylinder misfire, overheating again changed the reservior cap, no overheating for another week, TODAY overheated all the way hot, mechanic says blown head gasket and $2000 is there any way this can be incorrect. also the heater wasnt working as of today.

    • By Austin Davis says:

      First, get a cooling system pressure test to determine there are no more leaks.

      If no leaks, check to make sure the electric cooling fans are working, and there is NO restriction in the radiator…sounds like the radiator has had some issues and would not be surprised if there is an internal problem with it restricting the flow of coolant.

      Once you have done that, I inspect the spark plugs and figure out what the misfire code is all about. If you have an internal cooling system problem, like a blown head gasket it will let coolant into the cylinder and cause the misfire. So either there is a headgasket type of problem or there is another type of problem, like worn or faulty spark plug or ignition coil etc. that is causing the misfire. A compression test of each cylinder might also help you determine if there really is an internal coolant leak.

      Having no hot air in the heater tells me there is no hot coolant in the engine, so where did the coolant go? A pressure test should help you determine that.

      If you have done all the steps above, and you still suspect a blown headgasket you might want to try the engine sealer additive I mention here on this page, although dont jump to conclusions rule everything else out first.

  54. Nicole Walbaum says:

    I have a 2005 1/2 2.5ltr inline 5 that has a cracked head or gasket. It was in the shop and I had radiator replaced. Also the fan and oil filter adaptor housing. It is leaking oil and my mechanic said it was either the head or the gasket. I don’t have a radiator cap, just the overflow tank. Can I use k&w and how would be the best way?

  55. Erin says:

    I recently purchased a 2002 Mercury Cougar and I drove it without any issues for two weeks. I had to replace the hood cable after buying it. I checked my fluids and everything looked good except the radiator reservior was a nasty foamy mess. I added water to it and then it started running hot. I took it to the shop and they replaced the thermostat, radiator, and water pump. It was ok for a few days and then the engine light came on. I was told it was a misfire in the 4th cylinder. A few days later starting the car became difficult. I took it back to the shop and they suspect it’s a head gasket. I have the white smoke, coolant odor, etc. They changed my spark plugs and discovered coolant pooling up. My car is still at the shop because they don’t work on internal engines. I attempted to retrieve my car today and I couldn’t get it to start. I need advice please. Thanks!

    • By Austin Davis says:

      Well, I think you need to start from scratch with another mechanic, hopefully a full service real mechanic. I would first start with getting a cooling system pressure test to determine if there truly is a coolant leak internally inside the engine. I would expect to see white smoke out exhaust, a check engine light on, a missfire with the engine so it runs rough and has less power and acceleration than before, and I would expect that you would be adding coolant to the radiator regularly.

      So, if your pressure test does show that an internal coolant leak is possible, then I would try the head gasket sealer additive I talk about on this page, and use it as per my instructions not those on the can. Its a cheap and inexpensive alternative option to replacing the head gaskets, which is going to cost you at least $1200.

      Keep us posted

  56. Bethany says:

    Hi Austin,
    So we replaced the radiator hoses, completly flushed the radiator and the resevoir, gave it an oil change and changed the filters. Nothing is visably leaking, and it sounds so much better, runs better, BUT it is still heating up. Should I try the K&W?

    • By Austin Davis says:

      I wrote to another reader recently, see if this helps you as well. Get back to me with what you find out.
      We want to know WHEN the engine overheats.






      So to recap. In your situation I would do the following

      1. Pressure test the cooling system for leaks.
      2. Check to make sure the electric cooling fan is working, or fan clutch if you have a real plastic fan on the engine

  57. Bethany says:

    Thanks Austin! The mechanic wrote on the sheet “OK for coolant leaks, has evgine damage”. I dont know how he would even know that without breaking the vehicle down. We are now in the process of changing out the hoses and flushing the radiator. I will let you know. I have a gut feeling he did not blow a head gasket. thanks again,

  58. Bethany says:

    My sons truck, 2003 Ford Ranger, is having issues just like these and come to think of it we used to take it to Jiffy Lube.
    His coolant resevoir looks like an orangish / chocolate mess as well. It started over heating and then we noticed it is not holding any coolant. It appears to have a pretty sizable leak in the lower radiator hose. Two different mechanics have “looked” at it but not torn the vehicle down and both have said they are “guessing” a possible blown head gasket. The oil looks good with no water in it. One guy wants $1000 and my mechanic for over 25 years years (who now has a new person working for him; hense the one who is guessing) they want a few thousand to break it down and fix. I do not trust them any longer as they diognosed my Honda Element incorrectly prior to this. What are your thoughts? He does go too long inbetween oil changes. When I drive it (which is very very rare, it is sitting until I fix it) it sounds a little rough but really not bad at all. Just like a little bit of an older truck.

    • By Austin Davis says:

      Did you replace or fix the lower radiator hose and the coolant leak is repaired? If not, do that first, flush out the radiator and coolant over flow bottle as best you can and top off with a 50/50 coolant mix. Drive the vehicle and see if you still have an overheating issue.

      A simple cooling system pressure test will determine if you have a coolant leak, either internally like a head gasket or externally like a water pump or hose. Do this first! Sometimes a leaking water pump will drip down the lower radiator hose and fool you into thinking the hose is at fault. I hate guessing, it just costs the customer money. So if your mechanic has not properly pressure tested or you can see an actual hole in the hose…find a real mechanic.

      IF, you have repaired the coolant leak, and done another pressure test and determined there is an internal leak and suspect the head gasket as the culprit, I would try the K&W Block Sealer additive I mentioned on this page. It seems to work wonders for many of my customers, and its something you can do yourself.

  59. Josie says:

    I have a 98 Cadillac Seville SLS with 116K miles.
    1. Had coolant flushed right after I bought it because of the gauge going a
    little past 1/2 and making me uncomfortable.
    2. Had a problem with the car running hot on the way home from out of town
    on the interstate. It would start going towards 3/4 on the gauge and I
    would stop and let it cool off. Would only be able to go about a mile
    before it did it again. The heater would not work – only blew cold air.
    Had someone come and follow me and was able to drive the car all the way
    home (about 30 miles) with the gauge going to 3/4 but never overheated. I
    had the thermostat replaced.

    3. After that, the gauge would go a little past normal but would go back to
    normal while driving. Then one day the car completely overheated (message
    came on and it shut a/c off) after driving about 2 miles. I had it towed
    back to the shop that replaced the thermostat. They said it needed a
    tensioner and serpentine belt because the belt wasn’t turning the water
    pump. Got all that done.

    4. Now car runs fine most of the time, but after driving for about 20
    minutes, the gauge will start going up and will go up to 3/4 but never
    higher, and then when I stop or slow down, or speed up the gauge goes back
    down to 1/2. There is no smoke, no discolored oil, no coolant smell, but
    the check engine light is on (auto zone told my cylinder 1 misfire so I
    assumed I needed to get a tune up).

    I called the shop to see if they might have put in the wrong or defective
    thermostat. He said he is wondering if the head gasket might not be the
    problem (which I have read is a common problem in these cars). But I would
    like your opinion.

    • By Austin Davis says:

      2 things jump out at me in your email.

      1. You said the heater was not hot when the engine was over heating. In order for the heater to be hot, there has to be hot coolant circulating inside the engine. No hot coolant, no heater. So, I would first pressure test the cooling system for leaks and rule out a leak in the system. This is a simple test that most mechanics can do while you wait. These vehicles are notorious for leaking intake gaskets.

      2. Seems the overheating issue happens when you have driven awhile on the freeway, which would tell me to look closely at the radiator for a restriction. Rust and calcium deposits will form at the bottom of the radiator which will restrict the flow of coolant, and this can not be “flushed out” only a new radiator will fix this issue. If you are sure there are no coolant leaks, I would take a gamble and replace the radiator with an inexpensive after market radiator from your local auto parts store.

      I would also get another mechanic, seems this one might be lost.

      I dont think you have a headgasket issue, not yet anyway from what you told me. Driving this car while overheating will definitely put stress on the headgaskets, so be careful letting the engine overheat.

      On the missfire, these engines are notorious for breaking the valve lifter support brackets. I would determine that the misfire is not due to a spark plug or spark plug wire, then remove the valve cover on the side with the missfire and inspect the aluminum brackets to see if one is broken. You can also do a compression test on that cylinder and if the compression is 0, then the bracket is likely broken and that cylinder is basically dead, causing the miss. You buy the bracket at the dealership.

  60. Pete says:


  61. AB says:

    Just want to point out, Ive been to Jiffy Lube multiple times, the last time I went th hey has actually put the wrong coolant in my car. I have a very picky oldsmoblile, that for some reason only takes 50/50. Once my regular mechanic checked my car due to it over heating. We discovered they used tbe wrong kind. Oil changes are much cheaper and trustworthy at an actual autoshop

  62. Justin says:

    If you mix to different coolants together like yellow and green some thing like that you will turn your coolant to sludge

  63. Billy Bob says:

    Git yer radiator boiled out.

Post a Reply to Robert sisson